The present invention relates to a dispenser device for dispensing a fluid substance in spray form. More particularly, the invention relates to a miniature spray device that is preferably disposable, and in particular suitable for spraying a sample in the pharmaceuticals, perfumery, or cosmetics fields.
The problems encountered for such a substance dispenser are, in particular, the requirements of being inexpensive to manufacture. Since samples are not generally intended for sale, their manufacturing cost must be as low as possible. It is thus important to have dispensers whose parts are easy to make on a mass-produced basis and which are particularly simple to assemble. Furthermore, since samples serve mainly for advertising purposes, it is desirable for the dispenser to be capable of bearing, in visible manner, the trademark, the logo or any other distinctive feature corresponding to the substance contained in the dispenser. Similarly, it is desirable to provide a device that has a shape that is both original and practical to use. For example, for samples to be included between the pages of magazines or journals, it is essential for the thickness of the dispenser to be very small.
A dispenser device of the invention may also have uses in the pharmaceuticals field. In this particular field, it is important for the dose or metered quantity of substance to be accurate. Furthermore, it is also important for the spray to be of good quality.
For example, it is known from Document FR-A-2 443 980 that a disposable vaporizer can be made by welding together sheets of plastic so that, between them, they define a reservoir and two swirl channels connected to a spray orifice. By pressing on the reservoir whose walls are made of sheets of plastic, the substance is delivered into the swirl channels and then cut through the spray orifice to create a jet of sprayed substance. However, that disposable vaporizer does not make it possible to expel a defined metered quantity of substance. In addition, forming the swirl channels by welding two sheets of plastic together is rather imprecise and haphazard. In a version of that vaporizer, the reservoir is subdivided into two chambers by a partition which breaks under the applied pressure. One chamber is filled with a fluid while the other contains some other substance and air. Furthermore, the reservoir is separated from the spray orifice by a weak point. Firstly, on pressing the reservoir, the partition breaks, and the two fluids mix to some extent with each other and with air. In any event, the resulting mixture cannot be homogeneous. By increasing the applied pressure, the weak point breaks and the non-homogeneous mixture is delivered to the spray orifice. The jet that is output via the orifice is made up sometimes of a first fluid, sometimes of a second fluid, and sometimes of air, but it is never made up of a homogeneous mixture of all three. Therefore, the jet is sometimes purely aqueous, and sometimes two-phase. Its quality is thus not constant.
Document FR-2 232 923 describes a dispenser of the same type and suffering from similar problems.
Document WO 98/01360 discloses a two-phase dispenser capable of delivering a metered quantity of substance in spray form. That dispenser is also organized to serve as a miniature spray device in the form of a sample. It comprises two reservoirs of air and one reservoir of substance, all three reservoirs being connected to a common spray orifice. Upstream from the spray orifice, a fiber is provided that is capable of being soaked with substance. The air expelled from the reservoir of air therefore passes through the fiber soaked with substance expelled from the two reservoirs of substance. To actuate the device, a press member is provided in the form of a tab that can be folded down over the reservoirs to flatten them, thereby causing both substance and air to be delivered to the spray orifice. The various reservoirs are formed between a backing and a flexible barrier film. The press tab causes the film to be flattened against the backing where the film and the backing co-operate to form the reservoirs of substance and of air.
A drawback of that type of two-phase dispenser is that the quality of the spray depends on the speed at which the tab is actuated against the reservoirs. If the tab is brought slowly against the reservoirs, the spray is of poor quality. Therefore, it is necessary to press down the tab at some speed.
An object of the present invention is to solve that problem of the prior art by defining a low-cost dispenser device that guarantees excellent spray quality under all circumstances. In addition, in certain uses, in particular for advertising, the dispenser must satisfy certain dimensional requirements, in particular if it is to be of very low thickness so that it can be incorporated in a magazine or a journal. Furthermore, it should be capable of withstanding high pressures without substance leaking out. When such a sample is included in a magazine and, for example, the magazines are stacked up, the included sample is subjected to a high pressure.
To solve that problem, the present invention proposes a dispenser device for dispensing a fluid substance in spray form, said device comprising a reservoir containing the fluid substance to be dispensed, and a spray orifice, said reservoir including at least one actuating wall that can be deformed by applying a pressing force so as to reduce the internal volume of the reservoir and thus to exert a pressure on the fluid substance so as to deliver it through the spray orifice, said at least one actuating wall having a predetermined threshold of resistance to deformation that must be overcome in order to deform it.
In an embodiment, said at least one actuating wall has a convex profile at rest, which rest profile is suitable for deforming suddenly and easily into a determined concave profile, when the pressing force reaches said resistance threshold.
Like the devices described in the prior art, the device of the invention is also actuated by pressing on an actuating wall, but, in the present invention, the state of deformation of the wall(s) does not depend linearly on the pressing force, but rather it requires a predetermined threshold to be exceeded so that energy is accumulated in the finger of the user, which energy is released suddenly when the force exceeds said resistance threshold of the wall. In this way, a sort of pre-compression is obtained, although the liquid inside the reservoir is not subjected to any pressure so long as the wall is not deformed. The potential energy accumulated in the finger of the user ensures that, on release, there is sufficient energy to achieve good spraying of the substance. In dynamic manner, so long as the pressing force has not reached said threshold, the wall remains at rest. As soon as the force exceeds this threshold, the wall leaves its rest position, and while it is deforming to its final deformed position, the force required is, in fact, considerably lower than the pressing force required to overcome the resistance threshold. As a result, after leaving the rest position, deformation takes place quickly and suddenly because the force is much higher than necessary. The rest position thus constitutes a point of resistance after which the force necessary to deform the wall is considerably lower to reach the final deformed state.
In an embodiment, said at least one actuating wall has at least one reinforcing rib or groove for increasing its rigidity or defining its periphery. The point of resistance is then formed by the grooves or the ribs.
According to another characteristic, said at least one actuating wall has shape memory enabling it to return to its initial shape after the pressing force is released. It is thus guaranteed that the dispenser can be used a plurality of times without spoiling the actuating capacity of the wall.
In addition, it is advantageous for said at least one actuating wall to have a constant deformed state so that the quantity of product dispensed is constant and metered. A dispenser having predetermined resistance to deformation, shape memory, and constant deformed state guarantees that an accurate metered quantity of substance is sprayed repeatedly with optimum quality. When the dispenser is used for two-phase spraying, the use of one or two actuating wall(s) of the invention is particularly advantageous because the actuating wall does not act directly on the fluid substance, but rather it acts on the gas inside the reservoir by compressing it suddenly.
In an advantageous embodiment for two-phase use, an insert comprising a retaining piece of porous material suitable for becoming soaked with fluid substance is disposed upstream from the spray orifice. The porous retaining piece is automatically soaked with fluid substance by capillary action when the dispenser is at rest, and it then passes a flow of air which is put under pressure by actuating the wall of the reservoir.
According to another characteristic, the spray orifice is hermetically sealed off by a stopper member before the dispenser is used. Therefore, any actuating of the wall merely causes the air inside the reservoir to be compressed, without any spray being emitted. The stopper member thus serves as a safety member and as a guarantee that the dispenser has not yet been used for the first time.
In a practical embodiment, the dispenser device may be made up of a thermoformed shell forming the actuating wall and of a closure film, the shell and the film co-operating to define the reservoir and the spray orifice. The dispenser can thus be manufactured very simply and rapidly on a single assembly line.
In a variant, the dispenser may be made up of two thermoformed shells, each of which forms an actuating wall, the two shells being assembled together in sealed manner, so as to form the reservoir and the spray orifice between them.